Blade Sharpening Stand

ABSTRACT

A blade sharpening stand including a support base body comprised of a pair of supporting stands spacedly provided, a blade set plate swingably attached at its rear side to the rear end of the support base body, a blade holder provided in the blade set plate for holding a blade of a knife on the blade set plate, and a guide roller provided on the front end of the support base body in a manner bridging the pair of supporting stands. A blade is held by the blade holder on the blade set plate after the blade set plate is set at desired inclined angle, and a grind stone set on the cutting edge of the blade and on the guide roller is moved back and forth to sharpen the cutting edge of the blade.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a blade sharpening stand and more specifically to a blade sharpening stand used when sharpening the cutting edge of, for example, a kitchen knife blade.

2. Description of the Related Art

Sharpening the cutting edge of the blade of a cutting tool such as a kitchen knife is usually done by an electric knife sharpener, and it is also done manually. When a cutting tool is sharpened manually, a grind stone, typically in a rectangular block shape, is set on a flat surface, and the blade of a knife held at its handle by one hand of an operator is placed on the top surface of the grind stone, and then operator moves the blade back and forth along the length of the grind stone while pressing the blade, particularly, near the cutting edge, against the grind stone. This operation is done in the same manner for both a chisel shape blade (or a single-edge blade) and a wedge shaped knife (or double-edged blade).

So as to produce an ideal or intended sharp cutting edge, it is preferable to use a grind stone that has a smooth sharpening surface with no concavities nor convexities thereon, and it is also preferable that the operator give constant pressing force to the blade during the sharpening action and further keeps the sharpening angle between the cutting edge of a blade and the sharpening surface of a grind stone constant during the entire sharpening process. However, it is not easy to always satisfy these sharpening conditions, particularly to keep the sharpening angle between the cutting edge and the sharpening surface of a grind stone constant during the entire sharpening process, and it is almost not possible to obtain an expected result in forming of a blade shape and an intended result in sharpening of the cutting edge. It is indeed not safe and not good practice to place fingers near the cutting edge during the sharpening action.

BRIEF SUMMARY OF THE INVENTION

Accordingly, it is an object to provide a blade sharpening stand that can help easy and assured sharpening action of a blade of a cutting tool such as a knife, kitchen knife, etc. without the difficulties seen in the conventional cutting tool sharpening.

The above object is accomplished by a unique structure of the present invention for a blade sharpening stand in which the sharpening stand comprises:

-   -   a support base body formed by a pair of supporting stands         spacedly provided;     -   a blade set plate swingably attached at its rear side to one end         of the support base body, the blade set plate being provided at         its front side with a securing means engaged with another end of         the support base body;     -   a blade holder provided in the blade set plate so as to hold a         blade of a knife on the blade set plate; and     -   a guide roller provided on another end of the support base body         in a manner that it bridges the pair of supporting stands.

With the structure above, a blade of a cutting tool such as a kitchen knife is set on the blade set plate and then held in immovably by the blade holder, and the blade set plate is adjusted for its inclination at appropriate angle with respect to a horizontal plane and then secured at that angle by a securing means. A grind stone is placed on the cutting edge of the blade and on the guide roller and then moved back and forth and zigzag, thus sharpening the cutting edge of the blade. Since the blade set plate can be moved in a swingable fashion for its desired inclined angle and fixed at that angle, the cutting edge of the blade that is held on the blade set plate by the blade holder can be sharpened at an intended angle. Once the blade set plate is set at an intended inclined angle, the angle does not change by being secured by a securing means, and thus the angle between the edge of the blade and the sharpening surface of the grind stone does not change either during the sharpening process; and accordingly, the cutting edge is sharpened at intended angle for its entire length.

In the above-described structure of the present invention, the blade holder is movably provided so that a distance or position of the blade holder from a rear side of the blade set plate can be changed. Accordingly, any size of blade can be held by the blade holder on the blade set plate; in other word, a cutting tool in any size can be sharpened with the sharpening stand of the present invention.

In addition, the pair of supporting stands are formed with curved vertical guide grooves. Accordingly, when making swing motion or when the blade set plate is set for its inclined posture, the blade set plate is guided along the curved vertical guide grooves, and inclined setting of the blade set plate can be made easily and smoothly; and further since the swingable blade set plate can be set at any desired angle when guided and rotated via the guide groove, even a very minute inclination angle adjustment, for instance 15-20 degrees, can be made, thus making it possible to sharpen the cutting edge of a blade for less than 1 mm in height (or to sharpen a 1 mm range from the very tip end of the blade edge), which is almost impossible when sharpening is done by hand while pressing and moving a blade on a grind stone.

Furthermore, the blade set plate can be provided on its under surface with a magnet. With this structure, the blade of a knife can be securely held on the blade set plate in addition of the pressing force provided by the blade holder.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a perspective view of a blade sharpening stand according to the present invention;

FIG. 2 is an enlarged view of a guide roller used in the blade sharpening stand;

FIG. 3A shows the blade holder of the blade sharpening stand, and FIG. 3B shows a manner of function thereof;

FIG. 4 is a perspective view of the blade sharpening stand with a knife set thereon; and

FIG. 5 is a perspective view of the blade sharpening stand in use.

DETAILED DESCRIPTION OF THE INVENTION

One embodiment of the blade sharpening stand according to the present invention is comprised of a support base body 10, a blade set plate 20 provided on the support base body 10, a blade holder 30 provided in the blade set plate 20, and a guide roller 40 set on the support base body 10.

The support base body 10 is comprised of a pair of supporting stands 11. The supporting stands 11 are, in this embodiment, substantially rigid metal plates that are connected to each other by a front connecting member 12F and a rear connecting member 12R with a certain distance (for instance, 8 inches apart) in between, so that the supporting stands 11 stand vertically. Each of the supporting stands 11 includes a front vertical frame 11F (of, for instance, 2 inches high) and a rear vertical frame 11R (of, for instance, 2.5 inches high). The front connecting member 12F connects the front vertical frames 11, and the rear connecting member 12R connects the rear vertical frames 11R, and each of the front vertical frames 11F is formed at top end thereof with a guide roller receiver 11G which is an arc-shaped recess for receiving therein one end of the guide roller 40 (see FIG. 2) which will be described later.

The blade set plate 20 is substantially a rectangular metal plate with its four side edges bent downward, thus forming an empty shallow box upside down. The blade set plate 20 thus formed is attached at one side 20R (or at its rear side) thereof to the upper end of the rear vertical frames 11R of the support base body 10 by, for instance, holding screws 26, so that the blade set plate 20 is swingably moved up and down as indicated with a curved arrow VT in FIG. 1. The blade set plate 20 can also be swingably mounted on the support base body 10 by a shaft (not shown) attached to the rear side of the blade set plate 20 and engaged at both ends thereof with guide holes formed in the upper end of the rear vertical frames 11R. The blade set plate 20 which is thus swingable or pivotable can be called a flapper. The width of the blade set plate 20 is substantially the same as (or slightly smaller than) the distance between the pair of the supporting stands 11 of support base body 10, and the length of the blade set plate 20 is substantially the same as the length (that is a distance between the front and rear vertical frames 11F and 11R) of the supporting stands 11, so that the blade set plate 20 covers substantially the entire interior space of the support base body 10 which (the space) is defined by the two supporting stands 11 and the front and rear connecting members 12F and 12R. The upper surface of the blade set plate 20 can be covered by a silicon or rubber film for avoiding slip of a blade of a cutting tool. In addition, a magnet 28 can be provided on the undersurface near the rear side 20R of the blade set plate 20 for attracting a metal blade of a cutting tool.

The front supporting stands 11 F are formed with curved (or arc-shaped) vertical guide grooves 14 that have the same circular arc as that of the swingable blade set plate 20 makes when the blade set plate 20 is swung or rotated up and down as shown by curved arrow VT in FIG. 1 about the above-described screws 26 or shaft. The blade set plate 20 can swing or rotate for the angle of 5 to 45 degrees with respect to a horizontal plane. At least one of the front supporting grooves 14 is provided on its outside surface with a curved scale 15 drawn along the curved vertical guide groove 14. The scale 15 is accompanied by numbers indicative of angles, for instance, 10 to 45 degrees, the blade set plate 20 is swung or rotated. The blade set plate 20 is provided at its both ends of the front side with tightening knobs (securing means) 22 that are slidably engaged with the curved vertical guide grooves 14 formed in the supporting stands 11. At least one of the tightening knobs 22 is screwed to the blade set plate 20, so that when the tightening knob 22 is loosened the blade set plate 20 is movable up and down to make its swing or pivot motion about its rear side 20R; and then after the blade set plate 20 is set at a desired position or at a desired inclined position, the tightening knob 22 is tightened, thus allowing the blade set plate 20 to be securely held at that position and thus allowing the blade set plate 20 to be set at the inclined position or the inclined angle.

Furthermore, the blade set plate 20 is provided with a blade holder 30 that is adapted to securely hold the blade of a cutting tool to be ground on the blade set plate 20. For this blade holder 30 to be allowed to move front-rear direction, the blade set plate 20 is formed with a pair of parallel longitudinal guide grooves 24 that extend in the front-rear direction of the blade set plate 20 (or parallel to the supporting stands 11).

The blade holder 30 is comprised of, as seen from FIG. 3A, a holding plate 30P and a pair of guide shafts 32 attached to the holding plate 30P. The holding plate 30P is of typically a rectangular metal plate with its front part bent downward for substantially 90 degrees, thus having a front bent portion 30F, and it is formed with a pair of lateral guide grooves 36 that respectively extend in a (lateral) length wise direction of the holding plate 30P. As seen from FIG. 3A, each of the guide shafts 32 (only one of the two is shown) is a screw comprising a screw head 34 and a shank portion 34S. The diameter of the screw head 34 is greater than the width of the lateral guide groove 36, and its shank portion 34S is within the lateral guide groove 36.

The blade holder 30 is mounted on (the upper surface of) the blade set plate 20 with the pair of guide shafts 32 (shank portion 34S) inserted through the longitudinal guide grooves 24 of the blade set plate 20. Each of the guide shaft 32 is mounted with a washer 32 a that is larger in diameter than the width of the longitudinal guide groove 24. Each guide shaft 32 is further mounted with a holding coil spring 32 b (called “holding spring 32 b”) so that one end (upper end) of the holding spring 32 b is in contact with the washer 32 a (or with bottom surface of the washer). At another end (lower end) of the guide shaft 32 is screwed with a butterfly screw (holding screw) 32 c, so that the holding screw 32 c is in contact with another end (lower end) of the holding spring 32 b. With these washers 32 a, holding springs 32 b and holding screws 32 c, the upper end portions of the guide shafts 32 project out of the (upper surface of) the blade set plate 20 so that a gap can be formed between the (lower surface of the) blade holder 30 and the (upper surface of the) blade set plate 20 as will be described below.

Instead of the screw 34 described above, the guide shaft can be formed by a securing screw 34′ screwed into the top end of a guide pipe member 34S′ which is an equivalent to the shank portion 34S of the screw 34. The diameter of the screw head of the securing screw 34′ is larger than the width of the longitudinal guide groove 24, and the guide pipe member 34S′ is within the longitudinal guide groove 36 of the holding plate 30P. On the guide pipe member 34S′, a washer (32 a) that is larger in diameter than the width of the longitudinal guide groove 24, a holding spring (32 b) and a butterfly (holding) screw 32 c are provided in the same manner as those provided on the screw comprising the screw head 34 and the shank portion 34S.

The holding plate 30P of the blade holder 30 is provided with a pressing lever 38 which is typically made of a metal. The pressing lever 38 is fixed at its one (root) end to substantially the center of the blade holder 30 by a rivet 38A so that another (tip) end portion of the pressing lever 38 sticks out over the front bent portion 30F of holding plate 30P. The pressing lever 38 can be rotatably attached to the blade holder 30 so that the tip end portion sticks out over the front bent portion 30F when the blade holding clip 38 is turned frontward and positioned parallel to the supporting stands 11.

When the pressing lever 38 is pushed down, overcoming the spring force of the holding spring 32 b, the rear edge 30R of the blade holder 30 is, as seen from FIG. 3B, raised or lifted with the bottom of the front bent portion 30F functioning as a lever fulcrum, thus forming a gap G between the holding plate 30P and the (upper surface of the) blade set plate 20, so that the blade (or the back of the blade) of a cutting tool to be ground is inserted into this gap G. With a release of pushing force from the pressing lever 38, the blade is held and set on the blade set plate 20 by the holding plate 30P by the spring force of the holding springs 32 b.

Furthermore, the blade holder 30 is formed with a pair of lateral guide grooves 36 on both sides of the pressing lever 38. The lateral guide grooves 36 are parallel to the rear side 20R of the blade set plate 20; and into these lateral guide grooves 36, the guide shafts 32 are inserted which are also, as described above, within the longitudinal guide grooves 24 of the blade set plate 20. With a combination of the lateral guide grooves 36 formed in the blade holder 30 and the longitudinal guide grooves 24 foamed in the blade set plate 20, the blade holder 30 can be moved on the blade set plate 20 not only in the lateral direction (a direction parallel to the rear side 20R of the blade set plate 20) but also in the longitudinal direction (a direction parallel to the supporting stands 11) for the length of the lateral and longitudinal guide grooves 36 and 24.

The blade sharpening stand according to the present invention further includes a guide roller 40, shown in FIG. 2, that is mounted on the support base body 10. The guide roller 40 is comprised of a central shaft 42, typically made of steel, and a plurality of roller elements 44 rotatably and spacedly provided on the central shaft 42, and it further includes end clips 46 at both ends of the central shaft 42 for keeping the roller elements 44 on the central shaft 42 and preventing the roller elements 44 from coming off from the central shaft 42. The roller elements 44 are hollow cylinders made of, for instance, transparent synthetic resins, stainless steel, etc. and provided on the central shaft 42 with spaces in between so as to be rotatable on the central shaft 42 and movable in the axial direction of the central shaft 42. The guide roller 40 is (as seen from FIGS. 4 and 5) mounted on the support base body 10 with its both end portions in the guide roller receiver 11G formed in the front vertical frames 11F of the supporting stands 11, so that it is parallel to the rear edge 3OR of the blade holder 30 and to the rear side 20R of the blade set plate 20.

In use, the sharper stand 10 is set on, preferably, a flat and horizontal surface. A silicon or rubber mat can be placed underneath so as to prevent the sharper stand from slipping during the use. As shown in FIG. 4, the blade 52 of a knife 50 is set on the blade set plate 20 in a manner that the cutting edge 52E of the blade 52 faces backward (and preferably, so as to stick out slightly from the rear side 20R of the blade set plate 20), and then the back 52B of the blade 52 is brought into the gap G or space formed between the blade set plate 20 and the blade holder 30. This gap G (see FIG. 3B) is formed, as described above, by pressing down (or by pressing toward the blade set plate 20) the pressing lever 38 overcoming the spring force of the holding springs 32 b, thus letting the rear edge 30R of the blade holder 30 rise.

The location of the blade holder 30 on the blade set plate 20 is adjusted so that the cutting edge 52E of the blade 52 slightly projects out of the rear side 20R of the blade set plate 20 and the blade holder 30 is substantially at the center of the blade 52 in the lengthwise direction of the blade 52. This adjustment is done by moving the blade holder 30 longitudinally, as shown by arrows LG in FIG. 3A, via the guide shafts 32 that are in the longitudinal guide grooves 24 of the blade set plate 20 and by moving the blade holder 30 laterally, as shown by arrows LT in FIG. 1, via the lateral guide grooves 36 of the blade holder 30, and then the holding screws 32 c provided on the guide shafts 32 of the blade holder 30 are tightened.

Upon completion of the positional adjustment of the blade 52 with reference to the blade holder 30, the grinding angle for the blade 52 is set by way of vertically moving the blade set plate 20 about its rear side 20R. This vertical swing motion of the blade set plate 20 along the arrow VT in FIG. 1 is made by moving the front side 20F of the blade set plate 20 up and down with the tightening knobs 22 being guided by the curved vertical guide grooves 14 formed in the supporting stands 11; and at desired angle read from the scale 15 next to the guide groove 14, the tightening knobs 22 are tightened. The blade set plate 20 having thereon the knife 50 is thus set at a desired inclination angle with respect to a horizontal plane (which is an imaginary horizontal plane passing the rear side 20R of the blade set plate 20). For instance, the blade set plate 20 can be set at 15-20 degrees inclination angle with respect to and underneath the horizontal plane which is most suited angle for sharpening a cutting edge of a knife having a cutting edge of 1 mm or less.

As shown in FIG. 5, a grind stone 60 is place on the cutting edge 52E of the blade 52 and on the guide roller 40, and it is moved back and forth and zigzag to grind and sharpen the cutting edge 52E. With the magnet 28 provided under the blade set plate 20, the blade 52 (if not made of ceramics) is attracted thereby and securely held on the blade set plate 20.

Though, in the above-described structure, the blade holder 30 includes a pair of guide shafts 32 and the blade set plate 20 is formed with a pair of (longitudinal) guide grooves 24, the blade holder 30 may include a single guide shaft 32, and the blade set plate 20 is formed only one guide groove 24 to comply with the single guide shaft for the movements of the blade holder 30 on the blade set plate 20.

In the present invention, since the blade holder 30 can be positioned at any desired location on the blade set plate 20 using the lateral and longitudinal guide grooves 24 and 36, substantially any size of blade can be set on the blade set plate 20 and sharpened; and since the blade is securely held by the blade holder 30, the blade can be sharpened evenly for the entire length and height. 

1. A blade sharpening stand comprising: a support base body comprised of a pair of supporting stands spacedly provided; a blade set plate swingably attached at one side thereof to one end of said support base body; a blade holder provided in said blade set plate for holding a blade of a cutting tool on said blade set plate; and a guide roller provided on another end of said support base body in a manner bridging the supporting stands.
 2. The blade sharpening stand according to claim 1, wherein said blade holder is movably provided so that a distance of said blade holder from said one side of said blade set plate is variable.
 3. The blade sharpening stand according to claim 1, wherein said blade holder is comprised of a holding plate, a guide shaft attached to the holding plate, a coil spring provided on the guide shaft, and a tightening screw screwed to the guide shaft, said guide shaft being inserted in a guide groove formed in said blade set plate.
 4. The blade sharpening stand according to claim 1, wherein said pair of supporting stands are formed with curved vertical guide grooves so that both ends of another side of said blade set plate is guided along said curved vertical grooves.
 5. The blade sharpening stand according to claim 1, wherein said blade set plate is provided with a magnet adapted to hold said blade of said knife on said blade set plate.
 6. A blade sharpening stand comprising: a support base body comprised of a pair of supporting stands spacedly provided; a blade set plate swingably attached at one side thereof to one end of said support base body, said blade set plate being provided with a securing means at another end thereof so that said blade set plate is set inclined by said securing means; a blade holder provided in said blade set plate for holding a blade of a cutting tool on said blade set plate; and a guide roller provided on another end of said support base body in a manner bridging the supporting stands.
 7. The blade sharpening stand according to claim 6, wherein said pair of supporting stands are formed with curved vertical guide grooves and said securing means is engaged with said guide grooves, so that the securing means is guided by said guide grooves and said blade set plate is set at desired inclined angle. 